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5-2 Greenhouse Effect

Page history last edited by Jay 9 years, 9 months ago



5.2 The Greenhouse Effect


5.2.1 Draw and label a diagram of the carbon cycle to show the processes involved.


This diagram depicts a carbon cycle:


5.2.2 Analyse the changes in concentration of atmospheric carbon dioxide using historical records.


The enhanced greenhouse effect and rapidly increasing growth in the level of atmospheric CO2 since 1958 measured at Mauna Loa, Hawaii is crucial evidence that the Earth is becoming warmer annually. Although there are many different reasons of global warming, scientists have found that human additions cause the significant increase in global warming. Before 1960s, the U.S. and other countries were not industrialized compared to 2010; there weren’t many factories and cars back a couple of decades ago. However, improvement in technologies, increasing demands on automobile production, booming in population, and increasing number of factories built are responsible for carbon dioxide emission in the atmosphere. Ususally, infra red radiation, which is a longer wave radiation, or heat, produced by the earth after receiving light from visible light, which is considered as short wave radiation


When there is an increase of carbon dioxide and other gases, the infra red radiation get trap in the atmosphere


5.2.3 Explain the relationship between rises in concentrations of atmospheric carbon dioxide, methane, and oxides of nitrogen and the enhanced greenhouse effect. Level 3


Greenhouse gases are the gases in the atmosphere that absorb infra-red radiation. Greenhouse gases are concentrated between the atmosphere and the earth.


-       Sun is a vital source for any living organism because it supplies energy that living organisms need.

-       Light wave is composed of two different types:

  - Visible light, which is considered as short wave radiation.

-   red radiation, which is a longer wave radiation- heat.

-   Gases that absorb infra-red radiation are called as greenhouse gases.

-       As the temperature of the earth increases through heating, the Earth radiates infra-red radiation back toward the space.

-       However, heat does not escape from the Earth; some heat is absorbed by the clouds, and some heat is absorbed by gases in the atmosphere.

-       Think of the Earth as a greenhouse; without greenhouse gases, the Earth would be very cold.

-       Both water vapour and methane are naturally occurring greenhouse gases.

-       Within last three decades, there has been an increase in demand for fuel and food increases in our human society, which means that there has been increase in          waste gases as well.

-       Some of the activities that people do that contribute to increase in waste gases are:

* Burning fossil fuel (e.g. gasoline in cars) and using catalytic converters for their exhaust systems;

* Using organic and commercial fertilizers to help crops grow better.

* Industrial processes (e.g the production of nitric acid.)

-       Methane is another major greenhouse gas. Following human activities can cause increase in greenhouse gases:

* Cattle Ranching- cows and bulls produce methane in their digestive tracts and release it into the atmosphere.

* Waste disposal in landfills- Organic wastes such as uneaten food materials decompose and release methane.

* Production and distribution of natural gases- When it is made, bottled or piped to homes, leaks in containers and conduits release methane into air.

What does it mean to have enhanced green house effect?

- Sunlight enters Earth’s atmosphere because the gases of the atmosphere are transparent to light.

- Most of the sunlight reflects off the surface of Earth and travels back out of the atmosphere- that is why astronauts can see Earth from space.

- Greenhouse gases retain some of the heat and trap it in the atmosphere.

- The end result of Earth’s natural greenhouse effect is that the atmosphere is warmer than outer space.



Even though, having some percentage of atmospheric carbon dioxide, methane, and oxides of nitrogen is necessary for maintaining the substantial temperature on Earth, rapid increase of these gases will cause increase in Earth temperature; if the temperature increases, global warming can happen real fast.





5.2.4       Outline the precautionary principle

So what is the precautionary principle?

The intergovernmental Panel on Climate Change (IPCC), was set up in 1988 to find out if human activities have an impact on climate.

-       Global temperature are increasing; global warming is not a hypothesis but a confirmed reality.

-       There is over a 90% chance that the cause of this increase in temperature is due to the production of greenhouse gases by human activity. The chance that these          fluctuations could be caused by natural phenomena alone is less than 5%.

-       Within the coming century, sea level is expected to rise between 18cm and 59 cm.

-       It is likely that severe weather events such as heat waves, drought or heavy rains will increase.


The precautionary principle holds that, if the effects of a human-induced change would be very large, perhaps catastrophic, those responsible for the change must prove that it will NOT DO HARM before preceding. This is the reverse of the normal situation, where those who are concerned about the change would have to prove that it will do harm in order to prevent such changes going ahead.


5.2.5       Evaluate the precautionary principle as a justification for strong action in response to the threats posed by the enhanced greenhouse effect.


The principle holds that those who wish to continue producing excess greenhouse gases should prove that there are no harmful effects before continuing. There will be some people, who work in industries like farming, manufacturing, transporting, and others, will question why they should be investing money to find new ways of reducing the greenhouse gases in their businesses when there is no solid evidence of global warming due to the greenhouse gases. Therefore, in order to save production cost, yet increase the sales cost, industrial workers will definitely bring out cheap and environmental harming methods. Despite the problem and possible harming, ecologically informed consumers will definitely choose products that are ecologically friendly


5.2.6       Outline the consequence of a global temperature rise on arctic ecosystems.


The Arctic consists of North America, Greenland, Iceland, and a part of Russia and Norway. Also includes the Arctic Ocean, over which floats a huge mass of ice surrounding the North Pole.


The Consequences:

-       More and more ice is melting every year;

-       There is less snow and more frozen rain in the winter;

-       Some regions which never had them before are now populated with mosquitoes;

-       Certain woody shrubs are proliferating on warmer soils where once there were only mosses and lichens on tundra;

-       Bird species such as robins have moved into areas where they are so foreign to the local people that a name for them does not exist in their language. (FUNNY!)

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